Abstract:

A releasable latch, for a motor vehicle lock mechanism, includes a fixed
stator having at least two semicylindrical portions, a rotor rotatably
mounted in the fixed stator and includes a plurality of tumblers
configured to be moved radially under an action of a key that is designed
to be inserted axially into the rotor, and an intermediate tubular socket
configured to rotate about an axis thereof in the fixed stator and to
move axially relative to the fixed stator. The rotor is directly coupled
with a control lever that acts as a earn when the key is suitable, and
uncoupled from the control lever in a released position. The rotor is
fixed axially in the intermediate socket, and the rotor and the
intermediate socket are prevented from rotating relative to one another
by the plurality of tumblers when the key is not suitable.

Claims:

1. A releasable latch, for a motor vehicle lock mechanism, comprising:a
fixed stator having at least two semicylindrical portions;a rotor
rotatably mounted in the fixed stator and comprising a plurality of
tumblers configured to be moved radially under an action of a key that is
designed to be inserted axially into the rotor; andan intermediate
tubular socket configured to rotate about an axis thereof in the fixed
stator and to move axially relative to the fixed stator;wherein the rotor
is directly coupled with a control lever that acts as a cam when the key
is suitable,wherein the rotor is uncoupled from the control lever in a
released positionwherein the rotor is fixed axially in the intermediate
socket, andwherein the rotor and the intermediate socket are prevented
from rotating relative to one another by the plurality of tumblers when
the key is not suitable.

2. The latch as claimed in claim 1, wherein the rotor and the intermediate
socket are connected in translation in a direction going from the cam to
a key entrance, against a force of a compression spring.

3. The latch as claimed in claim 1, further comprising an indexer
configured to be axially moved between a rest position and released
position,wherein under an effect of a rotation of the intermediate socket
relative to the fixed stator following the rotation of the rotor with an
unsuitable key, this indexer is connected in rotation to the cam.

4. The latch as claimed in claim 3, wherein the rotor and the indexer are
connected in translation.

5. The latch as claimed in claim 1, wherein the fixed stator comprises a
guidance and abutment contact block on an inner face thereof.

6. The latch as claimed in claim 5, wherein the intermediate socket
comprises a notch with inclined sides designed to receive said contact
block in an engaged position.

7. The latch as claimed in claim 3, wherein the indexer comprises inclined
faces designed to come against said contact block in the released
position.

8. The latch as claimed in claim 1, wherein two stator portions immobilize
a key head by means of a groove arranged at an end thereof.

9. The latch as claimed in claim 1, wherein two stator portions come to be
immobilized by means of a flange in an annular groove arranged on the
cam.

10. The latch as claimed in claim 2, further comprising an indexer
configured to be axially moved between a rest position and a released
position,wherein under an effect of a rotation of the intermediate socket
relative to the fixed stator following the rotation of the rotor with an
unsuitable key, this indexer is connected in rotation to the cam.

11. The latch as claimed in claim 2, wherein the fixed stator comprises a
guidance and abutment contact block on an inner face thereof.

12. The latch as claimed in claim 3, wherein the fixed stator comprises a
guidance and abutment contact block on an inner face thereof.

13. The latch as claimed in claim 4, wherein the fixed stator comprises a
guidance and abutment contact block on an inner face thereof.

14. The latch as claimed in claim 5, wherein the indexer comprises
inclined faces designed to come against said contact block in the
released position.

15. The latch as claimed in claim 2, wherein said two stator portions
immobilize a key head by means of a groove arranged at an end thereof.

16. The latch as claimed in claim 3, wherein said two stator portions
immobilize a key head by means of a groove arranged at an end thereof.

17. The latch as claimed in claim 4, wherein said two stator portions
immobilize via one of a key head by means of a groove arranged at an end
thereof.

18. The latch as claimed in claim 2, wherein said two stator portions come
to be immobilized by means of a flange in an annular groove arranged on
the cam.

19. The latch as claimed in claim 3, wherein said two stator portions come
to be immobilized by means of a flange in an annular groove arranged on
the cam.

20. The latch as claimed in claim 4, wherein said two stator portions come
to be immobilized by means of a flange in an annular groove arranged on
the cam.

Description:

[0001]The invention relates to a releasable latch for a motor vehicle lock
mechanism.

[0002]The addition of a release mechanism on a latch designed for a motor
vehicle lock makes it possible to prevent this latch from being forced.

[0003]Such a releasable latch is described in patent document WO02/097222.

[0004]Such a releasable latch, particularly for a motor vehicle lock
mechanism, comprises a fixed stator consisting of at least two
semicylindrical portions, a rotor that is rotatably mounted in the stator
and that comprises tumblers that can be moved radially under the action
of a key designed to be inserted axially into the rotor, the rotor being
coupled with a control lever, called a cam, when the key is suitable, and
uncoupled from the latter in the released position.

[0005]The release is carried out by means of ribs arranged on the inside
of the stator and the rotor is coupled to an output element equivalent to
a control lever, by means of a dog.

[0006]According to this known latch, the rotor and the dog guided in
rotation on the rotor are in a configuration that is substantially in an
end-to-end disposition. These two parts are substantially placed with one
as an extension of the other.

[0007]The dog comprises a main ring and guide lugs that extend axially
from the ring and that are designed to be received in matching axial
notches of the control lever.

[0008]This latch arrangement poses the following technical problems.

[0009]Through its configuration in end-to-end disposition, such a latch is
relatively long.

[0010]Furthermore, the dog is a relatively fragile part because of the way
it is made.

[0011]The parts forming this latch are relatively numerous and pose a
problem of angular clearance between them.

[0012]Furthermore, the constitution of the releasing device inside the
stator may cause the tumblers to lock relatively easily and wear of the
stator by these tumblers in the released position.

[0013]The invention solves these problems by proposing a particularly
compact releasable latch, that is to say of limited length, and of
particularly robust constitution.

[0014]To do this, the invention proposes a releasable latch, particularly
for a motor vehicle lock mechanism, comprising a fixed stator consisting
of at least two semicylindrical portions, a rotor that is rotatably
mounted in the stator and that comprises tumblers that can be moved
radially under the action of a key designed to be inserted axially into
the rotor, the rotor being coupled with a control lever called a cam when
the key is suitable, and uncoupled from the latter in the released
position, the latch characterized in that said coupling of the rotor and
of the cam is direct and in that the latch comprises an intermediate
tubular socket that is mounted so as to rotate about its axis in the
stator and that can be moved axially relative to the stator, the rotor
being fixed axially in the intermediate socket and the rotor and the
intermediate socket being prevented from rotating relative to one another
by the tumblers when the key is not suitable.

[0015]Such a latch has a particularly reduced space requirement. Its
length may be reduced by approximately 8 mm relative to a known latch. As
an example, it is possible to make a latch with a length of less than 45
cm and a diameter of less than 30 mm.

[0016]The efficiency of a latch according to the invention is further
enhanced since the drive train in normal operation comprises only two
parts in mutual engagement, the rotor and the cam.

[0017]According to a preferred embodiment, the rotor and the intermediate
socket are connected in translation in a direction going from the cam to
the key entrance, against the force of a compression spring.

[0018]Preferably, the latch also comprises an indexer that can be axially
moved between a rest position and a released position, under the effect
of a rotation of the socket relative to the stator following the rotation
of the rotor with the aid of an unsuitable key, this indexer being
connected in rotation to the cam.

[0019]Advantageously, the rotor and the indexer are connected in
translation.

[0020]The stator may comprise a guidance and abutment contact block on its
inner face.

[0021]Preferably, the intermediate socket comprises a notch with inclined
sides designed to receive said contact block in the engaged position.

[0022]And advantageously, the indexer comprises inclined faces designed to
come against said contact block in the released position.

[0023]According to the invention preferably said two stator portions
immobilize via one of their ends a key head by means of a groove arranged
at this end.

[0024]The key head may therefore be mounted independently of the parts
forming the latch and may be chosen according to required forcing or
corrosion stresses.

[0025]Advantageously, said two stator portions come to be immobilized by
means of a flange in an annular groove arranged on the cam.

[0026]The latch according to the invention has an enhanced resistance to
forcing whether it be to wrenching out or driving in.

[0027]This inviolability is also strengthened by a reduced angle at the
cam on the rear portion. The latch according to the invention has a
clearance angle at this level of less than 8° instead of
15° in the known latches.

[0028]The invention is described below in greater detail with the aid of
figures that represent only a preferred embodiment of the invention.

[0029]FIG. 1 is an exploded view in perspective of a releasable latch
according to the invention.

[0030]FIG. 2 is a view in perspective of the releasable latch according to
the invention, in the initial position.

[0031]FIG. 3 is a view in cross section in the prerelease position.

[0032]FIG. 4 is a view in perspective of a latch according to the
invention, in the engaged position, the stator being only partially
represented and the compression spring not being represented.

[0033]FIG. 5 is a view in perspective of a latch according to the
invention, in the released position, the stator being only partially
represented and the compression spring not being represented.

[0034]FIG. 1 shows a rotary latch with a longitudinal axis A1 comprising
release means according to the teachings of the invention. This latch is
represented in FIG. 2 in the initial position before the insertion of a
key.

[0035]The latch 10 essentially comprises a rotor 12 that is mounted so as
to turn, about the axis A1, inside a fixed stator 14 consisting of two
semicylindrical portions 14A and 14B, with interposition between the two
of an intermediate tubular socket 16 that is mounted in rotation about
its axis in the stator and that can be moved axially relative to the
stator.

[0036]This intermediate socket 16 comprises, close to its transverse face
turned toward the cam 24, over a portion of its periphery, a notch 16
whose sides are inclined. Furthermore, this socket is in abutment against
the rotor thanks to an annular flange 16B (visible in FIG. 3), in a
direction directed from the cam to the key entrance.

[0037]The rotor 12 is designed to be rotated with the aid of a key (not
shown) inserted axially into the rotor 12 through a key entrance 18
arranged in a front transverse face 20 of the rotor 12, which face 20 is
covered by a head cover 21 designed for example to be flush with the
outside of a bodywork panel (not shown) of the vehicle.

[0038]The rear axial end 22 of the rotor 12 is designed to rotate a
control lever or cylinder 24 of a lock mechanism (not shown) to allow the
immobilization and release of an opening element of the vehicle.

[0039]The rotor 12 is capable of rotating the control lever 24, only in
the presence of a suitable key, in an engaged position in which the rotor
12 and the control lever 24 are connected in rotation by means of an
interlocking arrangement. In a released position, the rotor 12 is no
longer able to rotate the lever 24.

[0040]A helical compression spring 30 is interposed between the stator 14
and the intermediate socket 16 to move the latter axially rearward toward
its engaged position.

[0041]The stator 14 has a generally cylindrical tubular shape, once the
two portions 14A, 14B are assembled, and it may comprise means (not
shown) that make it possible to mount and attach the latch 10 to the
vehicle. The stator comprises, on its inner face, an abutment and
guidance contact block 14C whose sides have a V shape that is tangential
relative to this inner face on each of its ends. In the engaged position,
the notch 16A of the intermediate socket is interlocked in this abutment
and guidance contact block 14C under the force of the compression spring
30.

[0042]In a known manner, the rotor 12 is designed to receive tumblers 32
arranged in transverse planes that succeed one another at regular
intervals in the direction of the axis A1 of the latch 10 and that are
received in matching housings of the rotor 12.

[0043]The tumblers 32 can be moved radially in the rotor 12 and they are
moved elastically to a protruding position in which they partially
protrude from the housings of the rotor 12.

[0044]On the other hand, when a suitable key is inserted into the rotor
12, the tumblers 32 are fully retracted radially inward in the rotor 12.

[0045]Therefore, when the suitable key is inserted into the rotor 12, the
latter may pivot freely relative to the cylindrical intermediate socket
16 and relative to the stator 14.

[0046]On the other hand, if an unsuitable key, or any other tool, is
inserted into the rotor 12, as illustrated in FIG. 3, the tumblers 34 are
not fully retracted and are received inside matching windows 36 arranged
in the intermediate socket 16. Therefore, the tumblers 34 prevent the
rotor 12 from rotating relative to the intermediate socket 16 which, for
its part, remains free to rotate relative to the stator 14.

[0047]An indexer 28 consists of an open ring that is clipped into a groove
23 arranged close to the end 22 of the rotor turned toward the cam 24.
The indexer 28 is therefore connected in translation with the rotor. On
this ring are arranged, in the direction of the cam, two tongues 28A, 28B
for fitment into the cam 24. On its face turned toward the rotor, the
indexer 28 comprises two inclined faces 28C and 28D. As will be seen
below, these two inclined faces butt against the abutment and guidance
contact block 14C of the stator in the released position.

[0048]The latch 10 also comprises a return spring 50 operating in torsion
and used to return the cam 24 to the initial position.

[0049]The operation of the latch according to the invention will now be
described with reference to the other figures.

[0050]In FIG. 4, a suitable key has been inserted into the rotor 12
through the key entrance 18 and the latch is therefore in the engaged
position. The tumblers 32 are therefore retracted inside the rotor 12
which may turn in the intermediate socket 16.

[0051]In this position, the rotor 12 may be turned with the key and
carries with it the cam 24 in rotation, releasing the lock.

[0052]The intermediate socket 16 remains immobile in rotation, connected
to the stator 14 by the abutment and guidance contact block 14C and the
indexer 28 turns freely with the cam 24 by means of its lugs 28A and 28B.

[0053]The rotation of the cam 24 is obtained by the rotation of the
following parts: key/rotor/cam.

[0054]At the end of travel, when the key is released, the return spring
50, of which one end is fixed and another end is in abutment against a
flange 24A of the cam 24, causes the cam to return to the initial
position and the dog and the rotor.

[0055]In FIGS. 3 and 5, an unsuitable key has been inserted into the rotor
12 through the key entrance 18 and the latch is therefore in the released
position. The tumblers 32 are therefore not retracted inside the rotor 12
which is consequently connected in rotation to the intermediate socket
16, by fitment of the tumblers in the latter.

[0056]The rotation of the unsuitable key therefore rotates the rotor 12
and the intermediate socket 16 which are connected. This intermediate
socket 16, through the interaction of one V side of the abutment and
guidance contact block 14C, turned toward the rotor, and an inclined face
of the notch 16A of the socket, is translated in the direction of the key
entrance against the force of the compression spring 30. By its annular
flange 16B, the intermediate socket 16 takes with it the rotor 12 in this
translation in the direction of the key entrance. The rotor then
disconnects from its interlocking with the cam 24. Furthermore, the rotor
12 and the indexer 28 being connected in translation, the indexer is also
moved in the same direction and its inclined faces 28C and 28D butt
against the V sides of the abutment and guidance contact block 14C,
turned toward the cam. In this position, it is immobilized and blocks the
cam by means of its meshing branches 28A, 28B.

[0057]The intentional rotation of the key therefore causes the movement of
the following parts: translation of the intermediate socket/translation
of the rotor/translation of the indexer/prevention of the cam from
rotating.

[0058]During the subsequent insertion of a suitable key, the rotor 12 is
turned, thanks to the rotation of the key, to the initial position
represented in FIG. 2, then the latch is engaged if the key is suitable
or is released if the key is not suitable.

[0059]The latch according to the invention is provided with an armored
rotor head 21, for example made of sintered steel. The two-portion stator
14 also enhances impact-resistance.

[0060]This latch has inviolability qualities that are increased relative
to the prior art.

[0061]The two stator portions 14A, 14B enclose the parts forming the latch
and, via one of their ends, immobilize the key head 21 by means of a
groove 21A, 21B arranged at this end and in which the key head is
interlocked. At their other end, they are immobilized by means of a
flange 24B, 24C in an annular groove 24D arranged on the cam 24.